Regensburg 2019 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 19: Hybrid and Perovskite Photovoltaics II
CPP 19.4: Talk
Tuesday, April 2, 2019, 10:15–10:30, H18
Characterisation of inorganic/hybrid lead and tin perovskites for efficient light-emitting diodes — •Ines Schmidt, Selina Olthof, and Klaus Meerholz — Universität zu Köln
Solution processable semiconducting perovskites have the general structure AMX3, where A is a cation (Cs, methylammonium (MA) or formamidinium (FA)), M is a metal cation (Sn or Pb) and X is a halide anion (I, Br or Cl). The combination of these results in 18 different primary (i.e. non-mixed) perovskites with bandgaps corresponding to a wide range of the electromagnetic spectrum. This bandgap tunability, very narrow emission characteristic and a high charge carrier mobility make perovskites promising candidates for light-emitting applications.[1] To gain better understanding regarding possible emission wavelengths as well as the absolute energy levels, we optimized and characterized this complete set of 18 material combinations using structural, electrical and optical measurement techniques. With that knowledge, multi-layer perovskite light-emitting diodes with an optimized energy alignment can be fabricated. To this end, we introduced crosslinkable hole-transporting layers into the device stack to improve charge injection. Another important aspect is the enhancement of charge carrier recombination, which is typically done by reducing the grain size in perovskite films. Therefore, we investigated the impact of different small organic molecules and polymer additives in the preparation procedure on perovskite morphology and device performance.
[1] Stoumpos, C. C et al., Inorg. Chem., 52(15), 9019-9038 (2013).